Radial seal for rotary heat exchanger



a f 5, A .AM/

H, RAHR ETAL RAIAL SEAL RoR ROTARY HEAT EXCHANGER Feb. 2.4, 1959Filedgnec. 2o, :195s

United States Patent n 'SEAL FDR ROTARY HEAT EXCHANGER Harold Rahr,Belmont, and Charles Wildman,Wellsville, N. Y., assignors to The AirPreheater Corporation, New York, N. 'Y acorporation of New York`Application December 20, 1956Serial No. 629,652

15 Claims. `(Cl. 257-6) The present invention "relates to heat `exchangeapparatus and particularly to improvedradial seals for use betweentherotor and `end plates of a housing enclosing the rotor of a rotaryregenerative air preheater or similar apparatus of theggeneral typedisclosedin the United States patent .of Hammond et al. 2,674,442, ofApril 6,

In'rotary regenerative air preheaters of the type described acylindrical rotor has compartments carrying heat transfer material whichas the rotor turns is first exposed to heating `gases and thendisposedin the vaix` passage to impart the absorbed heat to the air. Therotor is surrounded by a housinghaving end or sector plates formed withopenings to. provide fonthe flow. of` gas and alr. titionsformi-11gthe,rotorl comparnnentsyare provided with radial sealingmembers that wipe against the-imperforate portions of the sector plates.

The .present invention is directed to an improved arrangement by whichthe radial sealing members are imparted complete freedom of movement notsubject to the thermal distortions of the radial partitions. However,the invention will be more completely understood upon consideration ofthe following detailed description of an illustrative embodiment thereofwhen read in conjunction with vthe accompanying drawings in which:

Figure 1 is a sectional elevational view in diagrammatic form of arotary regenerative air preheater.

Figure 2 is an enlarged fragmentary view showing the relationshipbetween a radial seal and the end plate at one side of the rotor.

Figure 3 is a fragmentary view in section as seen on line 3-3 of Figure2.

Figure 4 is a fragmentary perspective view illustrating the relationshipbetween the radial partition and the radial sealing means.

In the drawings the numeral designates the cylindrical shell of a rotordivided into sector shaped compartments by radial partitions 11connecting it with a rotor post 12 which is driven by a motor andreduction gearing 13 to turn the rotor slowly about its axis. The rotorcompartments contain regenerative heat transfer material in the form ofmetallic plates 14 which first absorb heat from hot gases entering thepreheater through a duct 15 from a boiler or other source to bedischarged after passing over the heat transfer plates 14 through anoutlet duct 16 to which an induced draft fan (not illustrated) isconnected. As the rotor turns slowly about its axis the heated plates 14are moved into the stream of air admitted through the duct 17. Afterpassing over the plates 14 and absorbing heat therefrom the stream ofair is conveyed to the boiler furnace or other place of use through duct18.

A housing 20 enclosing the rotor 10 is provided at either end oppositethe rotor with end or sector plates 21 which are apertured at 22 and 23to admit and discharge streams of gas and air owing through the rotor.The radial partitions 11 are provided with radial sealing To preventthemingling of the two fluids, the par- 2,874,939 Patented Feb. 24, 119592.2 members 62 which are adapted to bear against the imper'forateportions of thesector plates to prevent-the ow offluids across `the endsof the rotor. In order that the streams of gas and air do nottbypass therotor by owing through the annular clearance space .24 between theYrotor shell 10 and the housing 20, it is customary to providecircumferential seals indicated diagrammatically-at 2S -on shell 19which wipe against confronting parts of sector plates 21,so as `to sealoff the space 24 from each end of the rotor.

In accordance with the present invention, the radial sealing arrangementcomprises.. anielongate channelmember 34 positioned over the end edgesof each diaphragm and extending radially between the rotor post and therotor shell. EachchanneLmember is1 provided with a span between oppositesidesthereof which is substantially greater thanthe edge thicknessof the`enclosed diaphragm 11 in `order that `the diaphragm may freely distortor laterally deform withinthe channel. vEach channel is provided withaplurality of tabs 36 with ports therethrough arranged. in alignmentwith similarportsfthrough the intermediate diaphragms as seen in Figure3. A first bushing 38 having a length substantially equal to thethickness ofchannelmember 34` is placed through the alignedopenings inthe tabs 36 .and the enclosed diaj phragm to link them together in orderthat each channel member may be substantially `iixed against `axialmovement. A small bushing 42 `at each` end of vthe `iirsttfbushing 38comprises spacing means whereby washers 44 `are maintained at aixeddistance from the .sides of the sealing channel 34. `Thespacelbetween each side `of channel 34 and the adjacent side of washer 44comprises` a U-shaped guideforside p1ate .48, one of which is littedloosely-at each side `of `cltlannelil. j-,Apluralityof .such guideassemblies radially spaced along the edge of each diaphragm maintainadjacent edges of said plates spaced apart in parallel relationship,while the remote edges thereof are maintained in a similarly spacedrelationship by bushings 52 extending therebetween. A pair of sealingstrips 62 are connected to side plates 48 by bolts 58 which also serveto connect radial extensions 66 thereto. The portion of these extensionswhich protrudes radially beyond the sealing strips provides a wearingsurface adapted to ride in grooves 64 formed by a cam member 67 carriedbeneath the imperforate portion of the end plate 21. The cam member 67is axially adjustable with respect to end plate 21 by an adjusting means68 which extends through the end plate and suitable packing means topermit adjustment during operation. This adjusting means 68 may beomitted when utilized at the lower edge of the diaphragm where gravityalone acting upon the axially movable sealing assembly will hold it inan abutting relationship with the adjacent sector plate.

A driving means 72 fixed to an end edge of each dia` phragrn extendsaxially thereof toward end plate 21 to support the sealing assembly34-62 and maintain it in substantial radial alignment during rotation ofthe rotor. By providing a lock nut 74 on the bolt S8 a section thereoflying between nut 74 and its head 76 may be arranged to cooperate withslot 78 as shown in Figure 3 to permit the sealing arrangement to beheld in its proper relationship.

When assembled as disclosed, the space at either side of partition 11within the channel member 34 permits extensive lateral distortion ofeach partition without restriction thereof so that relativelyundistorted sealing members 62 may at all times be held in sealingrelationship with an adjacent end plate.

During operation, clearance between the sealing members 56 and the endplate 21 may be adjusted as described to maintain an optimum ofefficiency throughout wide ranges of temperature variation and itsattendant thermal distortion; s

While this invention has been described with reference to the embodimentillustrated in the drawing, itis evident that numerous changes may bemade without departing 'from the spirit of the invention, and it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative only andnot in a limiting sense.

What we claim is:

1. A sealing arrangement for a regenerative air preheater or the likehaving a rotor including a cylindrical shell joined to a rotor post byradial partitions forming compartments that carry masses of heattransfer material and a housing surrounding the rotor and provided'opposite the latter with end plates including imperforate portionslocated between circumferentially spaced apertures formed in said platesAfor the ow of heating gases and air to and through the regenerativeheat transfer material carried by the rotor; radial sealing means'between the partitions and the end plates comprising elongate channelmembers adapted to t over the end edges of said partitions in axiallyabutting relationship; cam means mounted on the end plate arranged toextend axially into the space between the rotor and end plate; radialsealing means slidably embracing the outer side faces of said channelmembers; `and means mounted on the radial outer ends of the sealingmeans adapted to engage said cam means for support of the sealing meansindependently of the elongate channel member. I 2. A sealing arrangementfor a regenerative airpreheater or the like as defined in claim 1wherein thesides of the elongate channel member are spaced apart adistance substantially greater than the thickness of the encloseddiaphragm to permit relative movement therebetween.

3. A sealing. arrangement for a regenerative air preheater or the likehaving a rotor including a cylindrical 4 shell joined to a rotor post byradial partitions forming compartments that carry heat transfermaterial, and a housing surrounding the roter and provided at remoteends with end plates including imperforate portoins located betweencircumferentially spaced apertures formed in said plates for the flow ofheating gases and air to and through the regenerative heat transfermaterial carried by the rotor;4 radial sealing membersbetween thepartitions and the imperforate portionsof the end plates comprisingelongate channel members adapted to `tit over the end edges of saidpartitions 'inV axially abutting rela tionship; track means mounted onthe'end plates arranged to extend axially into theY spacebetweenfthe iroto'r and endV plates; parallel "side plates slidabl'yi'mbracing theside `face's-c'ithe channel members and extending axially thereof towardthe end plates; radially extending sealing strips xed to the parallelside plates to bridge the space between theside plates and the adjacentend plate; and means at the outer end of the sealing strips adapted toengage the track for supporting the sealing bars in sealing relationshipwith said end plate..

4. A sealing arrangement for a regenerative Vair preheater as recited inclaim 3 wherein the track means is mounted radially outward from theimperforate portion of the end plate.

5. A sealing arrangement for a regenerative. lair preheater as recitedin claim 3 having driving lmeans depending from the radial partitionsslidably supporting the ,ra-` dial sealing means for axial movement intoa sealing relationship with the imperforate portion of said end plate.

References Cited in the le of this patent UNITED STATES PATENTS Hammondet al. Apr. 6, 1954.A

